/*
Copyright (C) 1996-1997 Id Software, Inc.

This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.

*/

#include "quakedef.h"


/*

*/

typedef struct
{
    int				s;
    dfunction_t		*f;
} prstack_t;

#define	MAX_STACK_DEPTH		32
prstack_t	pr_stack[MAX_STACK_DEPTH];
int			pr_depth;

#define	LOCALSTACK_SIZE		2048
int			localstack[LOCALSTACK_SIZE];
int			localstack_used;


qboolean	pr_trace;
dfunction_t	*pr_xfunction;
int			pr_xstatement;


int		pr_argc;

char *pr_opnames[] =
{
    "DONE",

    "MUL_F",
    "MUL_V",
    "MUL_FV",
    "MUL_VF",

    "DIV",

    "ADD_F",
    "ADD_V",

    "SUB_F",
    "SUB_V",

    "EQ_F",
    "EQ_V",
    "EQ_S",
    "EQ_E",
    "EQ_FNC",

    "NE_F",
    "NE_V",
    "NE_S",
    "NE_E",
    "NE_FNC",

    "LE",
    "GE",
    "LT",
    "GT",

    "INDIRECT",
    "INDIRECT",
    "INDIRECT",
    "INDIRECT",
    "INDIRECT",
    "INDIRECT",

    "ADDRESS",

    "STORE_F",
    "STORE_V",
    "STORE_S",
    "STORE_ENT",
    "STORE_FLD",
    "STORE_FNC",

    "STOREP_F",
    "STOREP_V",
    "STOREP_S",
    "STOREP_ENT",
    "STOREP_FLD",
    "STOREP_FNC",

    "RETURN",

    "NOT_F",
    "NOT_V",
    "NOT_S",
    "NOT_ENT",
    "NOT_FNC",

    "IF",
    "IFNOT",

    "CALL0",
    "CALL1",
    "CALL2",
    "CALL3",
    "CALL4",
    "CALL5",
    "CALL6",
    "CALL7",
    "CALL8",

    "STATE",

    "GOTO",

    "AND",
    "OR",

    "BITAND",
    "BITOR"
};

char *PR_GlobalString (int ofs);
char *PR_GlobalStringNoContents (int ofs);


//=============================================================================

/*
=================
PR_PrintStatement
=================
*/
void PR_PrintStatement (dstatement_t *s)
{
    int		i;

    if ( (unsigned)s->op < sizeof(pr_opnames)/sizeof(pr_opnames[0]))
    {
        Con_Printf ("%s ",  pr_opnames[s->op]);
        i = strlen(pr_opnames[s->op]);
        for ( ; i<10 ; i++)
            Con_Printf (" ");
    }

    if (s->op == OP_IF || s->op == OP_IFNOT)
        Con_Printf ("%sbranch %i",PR_GlobalString(s->a),s->b);
    else if (s->op == OP_GOTO)
    {
        Con_Printf ("branch %i",s->a);
    }
    else if ( (unsigned)(s->op - OP_STORE_F) < 6)
    {
        Con_Printf ("%s",PR_GlobalString(s->a));
        Con_Printf ("%s", PR_GlobalStringNoContents(s->b));
    }
    else
    {
        if (s->a)
            Con_Printf ("%s",PR_GlobalString(s->a));
        if (s->b)
            Con_Printf ("%s",PR_GlobalString(s->b));
        if (s->c)
            Con_Printf ("%s", PR_GlobalStringNoContents(s->c));
    }
    Con_Printf ("\n");
}

/*
============
PR_StackTrace
============
*/
void PR_StackTrace (void)
{
    dfunction_t	*f;
    int			i;

    if (pr_depth == 0)
    {
        Con_Printf ("<NO STACK>\n");
        return;
    }

    pr_stack[pr_depth].f = pr_xfunction;
    for (i=pr_depth ; i>=0 ; i--)
    {
        f = pr_stack[i].f;

        if (!f)
        {
            Con_Printf ("<NO FUNCTION>\n");
        }
        else
            Con_Printf ("%12s : %s\n", pr_strings + f->s_file, pr_strings + f->s_name);
    }
}


/*
============
PR_Profile_f

============
*/
void PR_Profile_f (void)
{
    dfunction_t	*f, *best;
    int			max;
    int			num;
    int			i;

    num = 0;
    do
    {
        max = 0;
        best = NULL;
        for (i=0 ; i<progs->numfunctions ; i++)
        {
            f = &pr_functions[i];
            if (f->profile > max)
            {
                max = f->profile;
                best = f;
            }
        }
        if (best)
        {
            if (num < 10)
                Con_Printf ("%7i %s\n", best->profile, pr_strings+best->s_name);
            num++;
            best->profile = 0;
        }
    }
    while (best);
}


/*
============
PR_RunError

Aborts the currently executing function
============
*/
void PR_RunError (char *error, ...)
{
    va_list		argptr;
    char		string[1024];

    va_start (argptr,error);
    va_vsnprintf (string, sizeof(string), error, argptr);
    va_end (argptr);

    PR_PrintStatement (pr_statements + pr_xstatement);
    PR_StackTrace ();
    Con_Printf ("%s\n", string);

    pr_depth = 0;		// dump the stack so host_error can shutdown functions

    Host_Error ("Program error");
}

/*
============================================================================
PR_ExecuteProgram

The interpretation main loop
============================================================================
*/

/*
====================
PR_EnterFunction

Returns the new program statement counter
====================
*/
int PR_EnterFunction (dfunction_t *f)
{
    int		i, j, c, o;

    pr_stack[pr_depth].s = pr_xstatement;
    pr_stack[pr_depth].f = pr_xfunction;
    pr_depth++;
    if (pr_depth >= MAX_STACK_DEPTH)
        PR_RunError ("stack overflow");

// save off any locals that the new function steps on
    c = f->locals;
    if (localstack_used + c > LOCALSTACK_SIZE)
        PR_RunError ("PR_ExecuteProgram: locals stack overflow\n");

    for (i=0 ; i < c ; i++)
        localstack[localstack_used+i] = ((int *)pr_globals)[f->parm_start + i];
    localstack_used += c;

// copy parameters
    o = f->parm_start;
    for (i=0 ; i<f->numparms ; i++)
    {
        for (j=0 ; j<f->parm_size[i] ; j++)
        {
            ((int *)pr_globals)[o] = ((int *)pr_globals)[OFS_PARM0+i*3+j];
            o++;
        }
    }

    pr_xfunction = f;
    return f->first_statement - 1;	// offset the s++
}

/*
====================
PR_LeaveFunction
====================
*/
int PR_LeaveFunction (void)
{
    int		i, c;

    if (pr_depth <= 0)
        Sys_Error ("prog stack underflow");

// restore locals from the stack
    c = pr_xfunction->locals;
    localstack_used -= c;
    if (localstack_used < 0)
        PR_RunError ("PR_ExecuteProgram: locals stack underflow\n");

    for (i=0 ; i < c ; i++)
        ((int *)pr_globals)[pr_xfunction->parm_start + i] = localstack[localstack_used+i];

// up stack
    pr_depth--;
    pr_xfunction = pr_stack[pr_depth].f;
    return pr_stack[pr_depth].s;
}


/*
====================
PR_ExecuteProgram
====================
*/
void PR_ExecuteProgram (func_t fnum)
{
    eval_t	*a, *b, *c;
    int			s;
    dstatement_t	*st;
    dfunction_t	*f, *newf;
    int		runaway;
    int		i;
    edict_t	*ed;
    int		exitdepth;
    eval_t	*ptr;

    if (!fnum || fnum >= progs->numfunctions)
    {
        if (pr_global_struct->self)
            ED_Print (PROG_TO_EDICT(pr_global_struct->self));
        Host_Error ("PR_ExecuteProgram: NULL function");
    }

    f = &pr_functions[fnum];

    runaway = 100000;
    pr_trace = false;

// make a stack frame
    exitdepth = pr_depth;

    s = PR_EnterFunction (f);

    while (1)
    {
        s++;	// next statement

        st = &pr_statements[s];
        a = (eval_t *)&pr_globals[st->a];
        b = (eval_t *)&pr_globals[st->b];
        c = (eval_t *)&pr_globals[st->c];

        if (!--runaway)
            PR_RunError ("runaway loop error");

        pr_xfunction->profile++;
        pr_xstatement = s;

        if (pr_trace)
            PR_PrintStatement (st);

        switch (st->op)
        {
        case OP_ADD_F:
            c->_float = a->_float + b->_float;
            break;
        case OP_ADD_V:
            c->vector[0] = a->vector[0] + b->vector[0];
            c->vector[1] = a->vector[1] + b->vector[1];
            c->vector[2] = a->vector[2] + b->vector[2];
            break;

        case OP_SUB_F:
            c->_float = a->_float - b->_float;
            break;
        case OP_SUB_V:
            c->vector[0] = a->vector[0] - b->vector[0];
            c->vector[1] = a->vector[1] - b->vector[1];
            c->vector[2] = a->vector[2] - b->vector[2];
            break;

        case OP_MUL_F:
            c->_float = a->_float * b->_float;
            break;
        case OP_MUL_V:
            c->_float = a->vector[0]*b->vector[0]
                        + a->vector[1]*b->vector[1]
                        + a->vector[2]*b->vector[2];
            break;
        case OP_MUL_FV:
            c->vector[0] = a->_float * b->vector[0];
            c->vector[1] = a->_float * b->vector[1];
            c->vector[2] = a->_float * b->vector[2];
            break;
        case OP_MUL_VF:
            c->vector[0] = b->_float * a->vector[0];
            c->vector[1] = b->_float * a->vector[1];
            c->vector[2] = b->_float * a->vector[2];
            break;

        case OP_DIV_F:
            c->_float = a->_float / b->_float;
            break;

        case OP_BITAND:
            c->_float = (int)a->_float & (int)b->_float;
            break;

        case OP_BITOR:
            c->_float = (int)a->_float | (int)b->_float;
            break;


        case OP_GE:
            c->_float = a->_float >= b->_float;
            break;
        case OP_LE:
            c->_float = a->_float <= b->_float;
            break;
        case OP_GT:
            c->_float = a->_float > b->_float;
            break;
        case OP_LT:
            c->_float = a->_float < b->_float;
            break;
        case OP_AND:
            c->_float = a->_float && b->_float;
            break;
        case OP_OR:
            c->_float = a->_float || b->_float;
            break;

        case OP_NOT_F:
            c->_float = !a->_float;
            break;
        case OP_NOT_V:
            c->_float = !a->vector[0] && !a->vector[1] && !a->vector[2];
            break;
        case OP_NOT_S:
            c->_float = !a->string || !pr_strings[a->string];
            break;
        case OP_NOT_FNC:
            c->_float = !a->function;
            break;
        case OP_NOT_ENT:
            c->_float = (PROG_TO_EDICT(a->edict) == sv.edicts);
            break;

        case OP_EQ_F:
            c->_float = a->_float == b->_float;
            break;
        case OP_EQ_V:
            c->_float = (a->vector[0] == b->vector[0]) &&
                        (a->vector[1] == b->vector[1]) &&
                        (a->vector[2] == b->vector[2]);
            break;
        case OP_EQ_S:
            c->_float = !strcmp(pr_strings+a->string,pr_strings+b->string);
            break;
        case OP_EQ_E:
            c->_float = a->_int == b->_int;
            break;
        case OP_EQ_FNC:
            c->_float = a->function == b->function;
            break;


        case OP_NE_F:
            c->_float = a->_float != b->_float;
            break;
        case OP_NE_V:
            c->_float = (a->vector[0] != b->vector[0]) ||
                        (a->vector[1] != b->vector[1]) ||
                        (a->vector[2] != b->vector[2]);
            break;
        case OP_NE_S:
            c->_float = strcmp(pr_strings+a->string,pr_strings+b->string);
            break;
        case OP_NE_E:
            c->_float = a->_int != b->_int;
            break;
        case OP_NE_FNC:
            c->_float = a->function != b->function;
            break;

//==================
        case OP_STORE_F:
        case OP_STORE_ENT:
        case OP_STORE_FLD:		// integers
        case OP_STORE_S:
        case OP_STORE_FNC:		// pointers
            b->_int = a->_int;
            break;
        case OP_STORE_V:
            b->vector[0] = a->vector[0];
            b->vector[1] = a->vector[1];
            b->vector[2] = a->vector[2];
            break;

        case OP_STOREP_F:
        case OP_STOREP_ENT:
        case OP_STOREP_FLD:		// integers
        case OP_STOREP_S:
        case OP_STOREP_FNC:		// pointers
            ptr = (eval_t *)((byte *)sv.edicts + b->_int);
            ptr->_int = a->_int;
            break;
        case OP_STOREP_V:
            ptr = (eval_t *)((byte *)sv.edicts + b->_int);
            ptr->vector[0] = a->vector[0];
            ptr->vector[1] = a->vector[1];
            ptr->vector[2] = a->vector[2];
            break;

        case OP_ADDRESS:
            ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
            NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
            if (ed == (edict_t *)sv.edicts && sv.state == ss_active)
                PR_RunError ("assignment to world entity");
            c->_int = (byte *)((int *)&ed->v + b->_int) - (byte *)sv.edicts;
            break;

        case OP_LOAD_F:
        case OP_LOAD_FLD:
        case OP_LOAD_ENT:
        case OP_LOAD_S:
        case OP_LOAD_FNC:
            ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
            NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
            a = (eval_t *)((int *)&ed->v + b->_int);
            c->_int = a->_int;
            break;

        case OP_LOAD_V:
            ed = PROG_TO_EDICT(a->edict);
#ifdef PARANOID
            NUM_FOR_EDICT(ed);		// make sure it's in range
#endif
            a = (eval_t *)((int *)&ed->v + b->_int);
            c->vector[0] = a->vector[0];
            c->vector[1] = a->vector[1];
            c->vector[2] = a->vector[2];
            break;

//==================

        case OP_IFNOT:
            if (!a->_int)
                s += st->b - 1;	// offset the s++
            break;

        case OP_IF:
            if (a->_int)
                s += st->b - 1;	// offset the s++
            break;

        case OP_GOTO:
            s += st->a - 1;	// offset the s++
            break;

        case OP_CALL0:
        case OP_CALL1:
        case OP_CALL2:
        case OP_CALL3:
        case OP_CALL4:
        case OP_CALL5:
        case OP_CALL6:
        case OP_CALL7:
        case OP_CALL8:
            pr_argc = st->op - OP_CALL0;
            if (!a->function)
                PR_RunError ("NULL function");

            newf = &pr_functions[a->function];

            if (newf->first_statement < 0)
            {
                // negative statements are built in functions
                i = -newf->first_statement;
                if (i >= pr_numbuiltins)
                    PR_RunError ("Bad builtin call number");
                pr_builtins[i] ();
                break;
            }

            s = PR_EnterFunction (newf);
            break;

        case OP_DONE:
        case OP_RETURN:
            pr_globals[OFS_RETURN] = pr_globals[st->a];
            pr_globals[OFS_RETURN+1] = pr_globals[st->a+1];
            pr_globals[OFS_RETURN+2] = pr_globals[st->a+2];

            s = PR_LeaveFunction ();
            if (pr_depth == exitdepth)
                return;		// all done
            break;

        case OP_STATE:
            ed = PROG_TO_EDICT(pr_global_struct->self);
#ifdef FPS_20
            ed->v.nextthink = pr_global_struct->time + 0.05;
#else
            ed->v.nextthink = pr_global_struct->time + 0.1;
#endif
            if (a->_float != ed->v.frame)
            {
                ed->v.frame = a->_float;
            }
            ed->v.think = b->function;
            break;

        default:
            PR_RunError ("Bad opcode %i", st->op);
        }
    }

}
